18.4 Bacteria and Archaea
Kingdom Eubacteria Domain Bacteria
18.4 Bacteria and Archaea
Description
Bacteria are single-celled prokaryotes.
18.4 Bacteria and Archaea
Where do they live?
Prokaryotes are widespread on Earth.
( Est. over 1 billion types of bacteria, and over 1030 individual prokaryote
cells on earth.)
Found in all land and ocean environments, even inside other organisms!
18.4 Bacteria and Archaea
Common Examples
•
•
•
•
•
•
E. Coli
Tetanus bacteria
Salmonella bacteria
Tuberculosis bacteria
Staphylococcus
Streptococcus
18.4 Bacteria and Archaea
Modes Of Nutrition
• Bacteria may be heterotrophs or autotrophs
18.4 Bacteria and Archaea
Bacteria Reproduce How?
• by binary fission.
• exchange genes
during conjugation=
increases diversity.
conjugation bridge
• May survive by
forming
endospores =
specialized cell
with thick
protective cell wall.
•
TEM; magnification 6000x
Can survive for
centuries until environment improves. Have been found in mummies!
18.4 Bacteria and Archaea
• Bacteria Diagram
– plasmid = small piece of genetic material, can replicate
independently of the chromosome
– flagellum = different than in eukaryotes, but for movement
– pili = used to stick the bacteria to each
pili other or surfaces
plasma
membrance
chromosome
cell wall
plasmid
This diagram shows the typical structure
of a prokaryote. Archaea and bacteria
look very similar, although they have
important molecular differences.
flagellum
18.4 Bacteria and Archaea
• Classified by: their need for oxygen, how they gram
stain, and their shapes
18.4 Bacteria and Archaea
Main Groups by Shapes
– rod-shaped, called bacilli
– spiral, called spirilla or spirochetes
– spherical, called cocci
Lactobacilli: rod-shaped
Enterococci: spherical
Spirochaeta: spiral
18.4 Bacteria and Archaea
• Main Groups by their need for oxygen.
• obligate anaerobes
are poisoned by
oxygen
- Ex. Clostridium botulinum
- Ex. Clostridium tetani
– obligate aerobes
need oxygen
- Ex. Mycobacterium
tuberculosis
– facultative aerobes
can live with or without
oxygen
- Ex. E. Coli
18.4 Bacteria and Archaea
• Main Groups by Gram staining
– stains polymer peptidoglycan
– gram-positive stains purple, more peptidoglycan
– gram-negative stains pink, less peptidoglycan
Gram-negative bacteria have a thin layer of
peptidoglycan and stain red.
Gram-positive bacteria have a thicker
peptidoglycan layer and stain purple.
18.4 Bacteria and Archaea
– The amount of peptidoglycan within the cell wall can
differ between members of kingdom (eu)bacteria.
GRAM NEGATIVE
GRAM POSITIVE
18.4 Bacteria and Archaea
So, Why is Gram Staining Important?
• Different types of infectious bacterial diseases
respond differently to antibiotics when they are
gram- positive or gram-negative!
18.4 Bacteria and Archaea
KEY CONCEPT
How Bacteria help man.
18.4 Bacteria and Archaea
• Bacteria help ferment many foods.
– yogurt, cheese
– pickles, sauerkraut
– soy sauce, vinegar
18.4 Bacteria and Archaea
Bacteria provide nutrients to humans and other animals.
• Live in digestive systems of animals – LIKE US!!!.
– make vitamins (Ex. E. coli in our lg. intestine make B
vitamins for us!)
– break down food (Ex. Bacteria in cow stomach digest
cellulose in grass, hay, etc.
– fill niches
Human intestinal bacteria
18.4 Bacteria and Archaea
• Bioremediation uses bacteria to break down pollutants.
– oil spills
– biodegradable materials
18.4 Bacteria and Archaea
How Bacteria Hurt Man!
18.4 Bacteria and Archaea
Some bacteria cause disease.
• Bacteria cause disease by invading tissues or making
toxins.
• A toxin is a poison released by an organism.
Clostridium botulinum bacteria cause botulism food poisoning.
18.4 Bacteria and Archaea
• Example: Flesh Eating Bacteria
– may colonize new tissues
Flesh eating Streptococcus bacteria, normally do not harm us.
Only become dangerous when come in contact with other tissues like fat or muscle.
18.4 Bacteria and Archaea
18.4 Bacteria and Archaea
Antibiotics are used to fight bacterial disease.
• Antibiotics may stop bacterial cell wall formation.
• Antibiotics do not work on viruses.
• Prevention is best method to fight bacterial disease.
18.4 Bacteria and Archaea
Bacteria can evolve resistance to antibiotics.
• Bacteria are gaining resistance to antibiotics, due to:.
– overuse
A bacterium carries
(Handsanitizers?)
genes for antibiotic
resistance on a plasmid.
– underuse
(Take your RX as directed)
– misuse
A copy of the plasmid is
transferred through
conjugation.
(For livestock raising?)
– Read p. 565!
• Antibiotics must be
used properly.
Resistance is quickly
spread through many
bacteria.
18.4 Bacteria and Archaea
Bacteria play important roles in ecosystems.
• Prokaryotes have many functions in ecosystems.
– photosynthesize
– recycle carbon, nitrogen,
hydrogen, sulfur
– fix nitrogen = Nitrogen
fixation
Root nodules of white clover contain
Nitrogen fixing bacteria, which convert
atmospheric nitrogen into a form the
clover can use. The bacteria get
sugars from the clovers’ photosynthesis.
This is an example of mutualistic
symbiosis.
18.4 Bacteria and Archaea
Turn your pink sheet over, to put the Archaea on the
other side!!!!
18.4 Bacteria and Archaea
Kingdom Archaeabacteria, Domain Archaea
18.4 Bacteria and Archaea
Description
Archaeabacteria are single-celled prokaryotes that
live in extreme environments. They do NOT have
peptidoglycan in their cell walls.
18.4 Bacteria and Archaea
Where do they live?
•
•
•
•
•
Hot springs
Deep sea vents
Bottoms of Swamps
Mouths of volcanoes
Extra Salty lakes and seas
18.4 Bacteria and Archaea
Common Examples
• Methanogens = methane gas lovers
• Thermophiles = heat lovers
• Halophiles = salt lovers
18.4 Bacteria and Archaea
Modes of nutrition
• Heterotrophs and Chemoautotrophs
• Chemoautotrophs use chemicals in their environment to
create their own food
(Unlike photosynthesizers, that rely on energy from the
sun.)
18.4 Bacteria and Archaea
Reproduce how?
• Same as Eubacteria
18.4 Bacteria and Archaea
Diagrams (omit)
pili
plasma
membrance
chromosome
cell wall
plasmid
This diagram shows the typical structure
of a prokaryote. Archaea and bacteria
look very similar, although they have
important molecular differences.
flagellum
18.4 Bacteria and Archaea
Classified by:
• Shapes (See Eubacteria notes)- cocci, spirilli, bacilli
• Where they live
18.4 Bacteria and Archaea
Main Groups – see common examples
18.4 Bacteria and Archaea
Special roles in ecosystems – fill niches in extreme
environments
• Fill niches in extreme environments
• Many of them are chemosynthesizers